All is fair in love and war, and the spy shop has become America's new relationship weapon.

Feuding couples are using spy technology, from phone tracking and GPS to hidden cameras and microphones, to secretly record their partner's movements. Some try to use the evidence in divorce court proceedings to get custody of children.

Divorce attorneys say they've seen an increase in the role electronic data and social networking sites play in divorces, according to the American Academy of Matrimonial Lawyers.

Brian, a father in Texas who asked that his last name not be used, said he made a shocking discovery on a recent visitation with his young son. Brian claimed his ex-wife, Allison, stitched a tiny tape recorder into their son's jeans and was using the boy to spy on him.

"My son told me, 'Dad, Mom has all these recordings of us inside the house.' I said, 'what do you mean?'" Brian said. "'She has all these recordings and she listens to them at night.' And I pulled my son close to me and patted him down, and that's when I found the recorder."

Brian made a video recording of his own, showing what he said was documentation of the moment he found the recorder his wife had planted. His attorney has since filed a complaint in district court, alleging violation of wiretapping laws. In response, Brian's ex-wife told ABC News, "The allegation of wiretapping is inaccurate and is in the process of being dismissed through an agreement between he and I."

Her attorney added, "Brian is a three-time convicted felon. He is currently on parole... His federal lawsuit is nothing more than trying to gain the upper-hand in the family court."

Brian told ABC News that the charges are old and don't reflect on his parenting ability.

One of the primary reasons do-it-yourself snooping has become more widespread is because it is relatively cheap and easy. Surveillance equipment can cost less than $300, and spy gear that can't be found in a store can be bought online. Some recording devices are small enough to be mounted on a keychain, a motel room peephole, eyeglasses, pens or even inside a child's favorite toy.

"The one thing that's exchanged between the warring parties is the child, So the child becomes, in effect, some sort of Trojan horse." said John Kinney, a divorce attorney who has worked on a number of high-tech cases.

Duke Lewton has been on the other end of those devices in a vicious battle over his 7-year-old daughter, whose mother rigged her teddy bear with a microphone and told her to carry it at all times.

"[She] removed a few stitches, placed a recording device inside of the little bear's head, and then you could access a USB port on the side of the head ... and download all of our conversations that we had had through the weekend," Lewton told ABC News.

Lewton's wife was fined $10,000 for violating wiretapping laws and the tapes were thrown out of court.

But the law is murky. In 38 states, it is legal to secretly record in a public place. Federal wiretapping laws protect the privacy of your cell phone conversation and your computer, and most of the time, judges don't allow it.

"The emotions get so heated that people will do almost anything to get an edge," Kinney said. "If new technology provides avenues for collection [of] whatever evidence that a litigant might think is out there, they'll stop at nothing to get the evidence that they think they want."

And it's not just sparring spouses that are using spy technology. There is pre-nuptial snooping too.

Machell Russell had been living with her boyfriend Marcus Elias for three years when she started to suspect he was being unfaithful.

"He was telling me he needed to work late a lot, you know, and kind of rushing me off the phone when I would call him while I'm away on business," she said. "And I'm like, 'That's weird,' you know?"